System and Method for Fire-Polishing Glass Containers

ABSTRACT

A system and method for fire-polishing glass containers includes at least one fixed structure positioned on each side of a conveyor belt, in the forward movement direction of the glass containers; a structure that can move via each of the fixed structures, which moves with a forward movement in relation to the forward movement line of the conveyor belt, and with a backward movement in relation to the forward movement of said conveyor belt; a series of burners coupled to each of the moveable structures; sensors positioned on one side of the conveyor belt to determine the speed of the carrier belt and the distance or separation between containers; and a control means connected to the sensor means and moveable structure, for adjusting and synchronising the speed and distance of the containers.

FIELD OF INVENTION

The present invention refers to the production of glass containers andmore specifically to a system and method for fire polishing glasscontainers.

BACKGROUND OF THE INVENTION

Glassware such as glass bottles are usually produced in glasswareforming machines as those which can include multiple similar individualforming sections by the blow-blow process, while wide-mouth jars,glasses and other glass products are produced in forming machines knownas Series “E” and “F” by the press-blow process, the so-called “hotmold”. During the containers manufacturing process by means of theblow-blow or blow press process, the glass in the form of gob isintroduced into a parison or preformed mold in the parison formingstation, where, depending on the process, the gob settles by means of ablowing or vacuum process to the lower part of the parison mold to formthe crown of the container. Then, once the crown of the container isformed, a counter-blow is made to form the container parison or preform.Subsequently, the container preform is transferred by an invertmechanism with a 180-degree movement of the parison mold to a final blowmold of the forming station or final blow mold, where final shape isgiven to the container. Finally, the newly formed container is conveyedby a take-out mechanism to a dead plate at the front of the machine andthen transferred by means of a conveyor belt to a tempering furnacewhere the container is decorated or packed.

However, with regard to containers for the perfumery, cosmetics andpharmaceuticals industry, the objective of which are intended tomaintain and preserve the properties of the products they contain, it isrequired that containers be additionally treated with some method ofsurface polishing. The objective of these techniques is to remove somemanufacturing defects on the surface of the container such as roughness,tiny cracks, edges affecting the appearance of the containers such asgloss, transparency, etc.

There are currently some methods for polishing and brighteningglassware, such as immersing the item in a hydrofluoric and sulphuricacid mixture bath and then continuing with a washing step. However, theprocess is expensive and has a considerable environmental impact.

Another polishing and brightening technique is the fire polishingmethod, in which the surface of the glassware is exposed to a flame orheat. Due to the melting of the glass surface, the surface tensionsmooths the surface outwards, producing a smooth, shiny surface.

For example, U.S. Pat. No. 2,209,252 refers to an apparatus for glazingglassware to produce a high polish on both the exterior and the interiorof a glass article. Describes that the glass polishing is carried out intwo steps, first the exterior of the article is cooled while interiorthereof is polished. After, cooling fluid is directed into the interiorof the articles and an external polishing unit for polishing theexterior of the article. This is to prevent deformation of the productduring the polishing step.

The machine preferably uses an endless chain or conveyor belt that movesin a horizontal plane. This chain or conveyor carries a number ofvertical spacing articles-supporting spindles. The chain is adapted tocarry the articles beyond the different units. The chain is continuouslymoved and several operations are carried out by the different unitsduring operation of the chain. The machine to carry out this processincludes an endless chain or conveyor belt that moves in a horizontalplane. This chain or conveyor carries a number of item spacers. Thechain is adapted to carry the articles through different units. Thechain is continuously moved and operations are carried out by thedifferent units during operation of the chain.

Another type of machine for fire finishing glassware is described in theU.S. Pat. No. 4,265,651 from Jean Morel, which a frame, a verticalrotary assembly mounted on the frame, drive means for ensuring therotation of the vertical assembly which further comprises means forsupporting article supporting cups intended to move over a circular pathand burner holder means provided to follow the cups in their movement,wherein the supply of the burners is subjected to the action ofadjustable means for opening and closing the flows of fuel so that theburners are adjusted once and for all in optimum manner and it ispossible to vary the portion of path of the cups where fire-finishingtakes place. The invention is more particularly applied to themanufacture of glass articles whose shape may or may not be ofrevolution.

Even though some examples of a fire polishing machine for articles havebeen described, this type of process is currently carried out after thearticles have been formed in the forming machine and during theirtransfer to the tempering furnace. This process is carried out byplacing a first series of fixed burners on the first side of the line inparallel with the conveyor belt feed, and a second series of fixedburners are placed on the opposite side of the line, also on theconveyor belt feed line, in an out of phase position with respect to thefirst series of burners, so the glassware, when moved by the conveyorbelt, is exposed to a first flame or heat flow on the first side of thecontainer and then exposed to fire on the second side of the container.

In this case, burners are placed at different heights, to project theheat or flame flow to different areas of the glassware body, whilemoving on the conveyor belt. The exposure time of the glassware to fireis between 10 to 30 seconds, during that time the upper layers of theglass container are melted with no distortion.

However, during this kind of process, one of the problems is that duringthe passage of the glassware through the line of burners (which arefixed), they only polish their predetermined area for a few fractions ofa second, according to the forward speed of the conveyor belt.

Even though this process achieves a good quality of products, this typeof arrangement requires a greater number of burners per area, exposingthe product to a high intensity heat flow and short duration, whichcauses an overheating in the structure of the container, and may inducesome deformations in the surface of the container.

Therefore, this invention refers to a system and method for firepolishing glass containers, the objective of which is to improve theappearance of the container subjected to polishing by means of surfaceburners with natural gas and oxygen combination, using energyefficiently in specific areas of the container.

The system and method for fire-polishing glass containers includes: atleast a fixed structure placed on each side of the conveyor belt in aforward direction of the glass containers; a movable structure for eachfixed structures, which moves with a forward movement with respect tothe conveyor belt's forward line and with a backward movement withrespect to the forward line of the conveyor belt; each set of fixedstructure and movable structure, are placed in phase shifting inrelation to each other; a plurality of burners coupled by each movablestructures, which travel together with each movable structures at thesame forward speed of the conveyor belt provide a continuous flame orheat flow to each side of the container; sensing means in proximity tothe conveyor belt to determine the conveyor belt speed and distancebetween containers; and control means connected to the sensor means andmovable structure, to adjust and synchronize the speed and distance ofthe containers, to achieve better positioning of the burners and toabsorb any offset of the conveyor belt.

The system also includes flame detection sensors, which allow theequipment to switch on/off automatically in the following cases:

Start-up of the equipment.

Emergency shutdown.

No product on the conveyor belt.

Counting system for energy consumption.

This system allows to know the natural gas and oxygen consumption.

Objectives of the Invention

Therefore, a first objective of the present invention is to provide asystem and method for fire polishing glass containers, reducing thenumber of burners.

An additional objective of the present invention is to provide a systemand method for fire polishing glass containers, which allows by means ofsurface burners, natural gas and oxygen improve the appearance of thecontainer using the energy efficiently and the surface of each containercontinuously.

Another objective of the present invention is to provide a system andmethod for fire polishing glass containers, which allows the burners totravel a certain distance and in the same direction at the operatingspeed of the conveyor belt to carry out the polishing operation of thecontainers.

An additional objective of the present invention is to provide a systemand method for fire polishing glass containers, which allows adjustingany gap of the conveyor belt with respect to the positioning of eachburner.

An additional objective of the present invention is to provide a systemand method for fire polishing glass containers, which reduces thenatural gas and oxygen consumption.

An additional objective of the present invention is to provide a systemand method for fire polishing glass containers, where the containers areexposed at all times to a fixed area along the length of the containertracking, which allows the container temperature to be increased andachieve a better polishing quality.

These and other objectives and advantages of the present invention willbe evident to experts in the field of the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the production and handling process forglass containers showing the location of the system of the presentinvention;

FIG. 2 is a schematic diagram showing a side view of the system for firepolishing glass containers of the present invention;

FIG. 3 is a schematic diagram, in a plant view, of the fire polishingsystem for glass containers of the present invention;

FIG. 4 is a schematic diagram showing the side part of the system forfire polishing glass containers of the present invention and, alsoshowing the burners at different heights, in accordance with a secondembodiment of the present invention; and,

FIG. 5 shows a schematic diagram (according to FIG. 4), showing in theform of horizontal bars, the different forward and backward movements ofthe fire polishing system for glass containers, according to a secondembodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, the glassware forming process such as vessels orcontainers, the molten glass is fed from a feeder D in a gob form G,which are distributed by a distributor DG to the individual formingsections of an I.S. machine. The products formed by each of the stillhot sections S are first laid on a dead plate (not shown) in therespective section. Then the containers are pushed from there onto aconveyor belt (A) that moves the containers of all sections to atransfer mechanism T at the end of the section, which controls the flowof the products by separating them evenly and changing the flowdirection by 90° and placing them one by one on a cross conveyor BT inan evenly spaced row. Once a complete row of formed containers has beenformed, an pusher E simultaneously transfers all containers in the rowof the cross conveyor belt BT, through transition dead plates PM of alinear conveyor belt BL from an annealing furnace HT.

The location of the fire polishing system SP for glass containers inaccordance with this invention is schematically shown in FIG. 1.

The following will describe in detail each part and operation of thesystem of this invention according to FIGS. 2 and 3, which includes: afixed support structure 10 placed on each side of the conveyor belt (A),in the direction of the glass containers' advance. A movable structure12 coupled to slide on the fixed support structure 10, which moves witha forward movement at the same forward speed as the conveyor belt (A)and with a backward movement in the opposite direction to the feed rateof the conveyor belt (A). The movable structure 12 includes a lengthwisebar 16 coupled to the movable structure 12, which is fixed by means ofcross support bars 18, 20, at each of its ends. The lengthwise bar 16 iscoupled to a magnetic linear motor 22, which produces a straight linemovement, on which the lengthwise bar 16 and consequently the movablestructure 12 slide, with a forward and backward movement. At least oneseries of burners 24 are coupled on the movable frame 12, which arearranged toward the front of the conveyor belt (A) to provide a flame orheat flow to each side of containers 26. Burners 24 are mounted onburner holders (not shown) on the movable support structure 12, whichallow the height or angle of flame projection to be adjusted accordingto the height of items 26.

As shown in FIG. 3, the polishing system SP of this invention is placedon both sides of the conveyor belt (A), which are placed in acounterposition to each other, which are separated or offset by acertain distance. According to the layout shown, both movable structures12 move simultaneously, with a forward movement, up to a predeterminedfeed distance DA in the direction of continuous movement of the conveyorbelt (A) providing during its advance run, a flame on both sections ofthe containers 26. The movable structure 12 has a maximum run of 200 cm,but this may vary depending on the shape and size of the articles.

Once the movable structure 12 and burners 24 have completed the advancerun, the structure returns to its starting position (DI distance) toperform a new polishing step for containers 26 that are continuouslymoving on the conveyor belt (A). The polishing speed can be adjusted upto 2 m/s with a maximum reverse speed of 2 m/s.

Since burners 24 travel at the same speed as the conveyor belt (A),containers 26 require less exposure to fire, therefore, reduce thenumber of burners 24 allowing a considerable saving of gas and oxygen.According to the mode shown and based on the previous art, it waspossible to reduce the number of structures (SP) from 3 to 2, i.e. from18 to 12 burners.

Sensors 28 are placed on one side of the conveyor belt (A) to determinethe conveyor belt speed (A) and the distance or spacing (DE) betweencontainers 26; and, flame presence sensors 30, located in proximity toburners 24, allow the automatic on/off of the equipment in the followingcases: equipment start-up, emergency shutdown and absence of containerson the conveyor belt (A).

A programmable logic controller (PLC), connected via lines 32, 34, tothe magnetic linear motors 22 to move each movable structure 12. Thiscontroller (PLC) is also connected to sensors 28 through line 36 and toflame presence sensors 30 through line 38, to calculate and synchronizethe speed and space (DA) of containers 26, in real time, to achieve abetter positioning of burners 24 and to absorb any offset of theconveyor belt (A).

In a second embodiment of this invention, burners 24 are placed atdifferent heights, to project the flow of heat or flame towardsdifferent zones of the body of the glass containers 26, while theycontinuously advance on the conveyor belt (A). However, the advantageover the previous art is that the movable structure 12 is backed upseveral times before reaching its predetermined advance stroke (DA) (seeFIGS. 4 and 5) i.e. in a container line 26 on the conveyor belt (A),burners 24 and movable structure 12 advance a certain distance (d1), forexample, in a line of six containers, the first burners 24A project theheat flow to the bottom of the containers (1 and 2), the second burners24B project the heat flow to the middle of the containers (3 and 4) andthe third burners 24C project the heat flow to the top of the containers(5 and 6). Once the different areas of the containers 26 have beenexposed to the heat flow (e.g. ten to fifteen seconds), the movablestructure 12 moves back a second distance (d2), and now the first 24Aburners project the heat flow to the middle part of the containers (3and 4), the second 24B burners project the heat flow to the upper partof the containers (5 and 6) and move forward again, in that position, atthe same speed of the conveyor belt (A) at a distance (d2 n) projectingthe heat flow to each container 26 areas. Since this is a continuousprocess, the third burners 24C start projecting the heat flow to thenext row of containers 26, i.e. the bottom of the containers (1 and 2).

Once the different areas of containers 26 have been exposed to the heatflow for a period of ten or fifteen seconds, the movable structure 12moves back a third distance (d3) and again moves forward with the samespeed of the conveyor belt (A) a new distance (d3 n). As a result, thefirst burners 24A now project the heat flow to the top of the containers(5 and 6); the second burners 24B project the heat flow to the middlepart of the containers (3 and 4) and the third burners 24C project theheat flow to the lower part of the containers (1 and 2). The movablestructure 12 has a maximum run of 200 cm, but this may vary depending onthe shape and size of the items, so the movable structure 12 and burners26 can back up and move forward three or four times, projecting the heatflow to all of the container areas before reaching its forward distance(DA). Considering that the container rows 26 have a continuous movement,the movable structure 12 and burners 26 travel a maximum advance, whichwould be represented by DA=d1+d2 n+d3 n, and once reached, move back tothe starting distance D1.

In a third embodiment of this invention and on the basis of FIG. 2, allburners 24 may be automatically adjusted during the movable structure 12movement, i.e. all burners can direct a heat flow to all containers 26from the beginning, in a first area of the container (e.g. the bottom)in a first time period t1 and distance d1. Then, as containers 26 moveforward on the conveyor belt (A), burners 24 can be adjusted towards asecond area (e.g. the middle part of containers 26) in a second timeperiod t2 and distance d2 n; and finally, adjust burners 24 towards athird area (e.g. the top of containers 26) in a third time period t3 anddistance d3 n, until they reach their displacement or maximum distance(DA) and start their rewind step. In this case, burners 24 travel allthe time at the same speed of the conveyor belt (A) and its adjustmentto each of the different areas of containers 26 is set by theprogrammable logic controller (PLC).

From the above, the method for fire polishing glass containers comprisesthe steps of:

moving continuously forward a row of freshly formed glass containers ona conveyor belt;

providing a series of burners on at least one side of the conveyor belt;

exposing the containers to a burner flame, directing the flamecontinuously to the surface of each container up to a firstpredetermined advance distance DA for polishing the containers, saidburners travelling at the same forward speed as the conveyor belt (A);

moving the burners back to a starting distance D1, once the polishingstep of the containers has been carried out; and,

adjusting the conveyor belt speed, in real time, to achieve a betterpositioning of the burners on containers 26 and to absorb any offset ofthe conveyor belt (A).

The method of this invention including the step of: Sensing the conveyorbelt (A) speed and/or spacing (DE) between each container (26) to adjustthe burner tracking speed during polishing.

The method of this invention further includes the step of: projectingeach burner flame according to the shape of the container surface (26).

The method of this invention further includes the steps of: advancingthe movable structure 12 and burners 24A, 24B, 24C up to a distance (d1)to project the heat flow in a first predefined area of containers 26,which are continuously moving forward on the conveyor belt (A); movingback the movable structure 12 and 24A, 24B, 24C burners one distance(d2) to place them in a second predefined area of containers 26 and,again, moving the movable structure 12 and 24A, 24B, 24C burners forwardat the same conveyor belt speed (A) until distance (d2 n) is reached;moving back the movable structure 12 and 24A, 24B, 24C burners at adistance (d3) to place these burners in a third predefined area for eachcontainer 26 and, move the movable structure 12 and 24A, 24B, 24Cburners forward again at the same speed as the conveyor belt (A),projecting the heat flow to said third pre-defined area of eachcontainer 26, until distance (d3 n) that would be equivalent to themaximum advance distance (DA) of the movable structure 12 is reached;

moving back the movable structure 12 and burners 24A, 24B, 24C to astarting distance, once the fire polishing step of the containers hasfinished.

The method of this invention in a third embodiment includes the stepsof:

continuously moving forward a row of freshly formed glass containers ona conveyor belt;

providing a series of burners on at least one side of the conveyor belt,such burners travel at the same forward speed of the conveyor belt untila predetermined advance distance is reached;

adjusting the burners to direct a heat flow to all containers 26 in afirst container area in a first time period t1 and distance d1;

adjusting the burners to a second area of containers 26, to direct heatflow to the selected area in a second time period t2 and distance d2;

adjusting the burners 24 towards a third area of containers 26, todirect a heat flow to a third selected area in a third time period t3and distance d3, until the predetermined advance distance is reached;and

Moving the burners back to a starting distance, once the polishing stepof the containers has been carried out.

From the foregoing, a system and method for fire polishing glasscontainers has been described and it will be apparent to industryexperts that other possible advances or improvements can be made, whichmay be considered within the field determined by the following claims.

1. A system for fire-polishing glass containers includes: at least onefixed structure positioned on each side of a conveyor belt in a forwarddirection of the glass containers; a movable structure for each fixedsupport structure, which moves with a forward movement relative to theforward direction of the conveyor belt and with a backward movement inthe opposite direction to the forward direction of said conveyor belt; aplurality of burners coupled to each of the movable structures, whichtravel together with each of the movable structures at the same forwardspeed of the conveyor belt, to provide a flame or heat flow to thesurface of the container; sensing means positioned in proximity with theconveyor belt to determine the conveyor belt speed and distance betweencontainers; and control means connected to the sensing means, movablestructure and burners, to adjust and synchronize the speed and distanceof the containers, with respect to the burners and to absorb anydephasing of the conveyor belt.
 2. The system for fire polishing glasscontainers, as claimed in claim 1, where at least one fixed structureand a movable structure are placed on either side of the conveyor belt,in opposed facing manner, which are separated or offset with a spacingor distance to simultaneously move with a forward and backward movement.3. The system for fire polishing glass containers as claimed in claim 1,further including: flame presence sensors for automatic on/off burnersin case of: equipment start-up, emergency shutdown and absence ofcontainers on the conveyor belt.
 4. The fire polishing system for glasscontainers as claimed in claim 1, wherein burners are located atdifferent heights to project the heat flow or flame in steps topredetermined areas of the container, while advancing said containerscontinuously on the conveyor belt, such movable structure, and suchburners having several forward and backward movements to project theheat flow to all areas of each container until a predetermined forwarddistance is reached.
 5. The fire polishing system for glass containersas claimed in claim 1, wherein the burners are automatically adjusted bythe control means, to project the heat flow according to different areasof the container, as they continuously move forward on the conveyor beltuntil a predetermined forward distance is reached.
 6. The fire polishingsystem for glass containers, as claimed in claim 1, where the controlmeans is a programmable logic controller.
 7. A method for fire polishingglass containers comprising the steps of: continuously advancing a rowof freshly formed glass containers on a conveyor belt; providing aplurality of burners on a least one side of the conveyor belt; exposingthe containers to a burner flame, directing the flame continuously onthe surface of each container up to a first advance distance DA, toperform polishing of the containers, said burners traveling at the sameforward speed of the conveyor belt; moving the burners back to astarting distance DI, once the polishing step of the containers has beencarried out; and, adjusting the speed and distance of the containers, inreal time, to achieve better burner positioning and to absorb any phaseshift of the conveyor belt (A).
 8. The method to fire polish glasscontainers as claimed in claim 7 including the step of: sensing thespeed of the conveyor belt and separation between containers, to adjustthe tracking speed of the burners during polishing.
 9. The method tofire polish glass containers in accordance as claimed in claim 7 furtherincludes the step of: aligning is each burner flame according to theshape of the containers.
 10. The method for fire polishing glasscontainers as claimed in claim 7, wherein the step of providing aplurality of burners to at least one side of the conveyor belt includesthe step of: placing burners on the line of advance of the conveyorbelt, said burners being arranged opposed and spaced a distance fromeach one another; and, simultaneously moving the burners located on eachside of the conveyor belt with a forward and backward movement accordingto the advance of the containers on the conveyor belt.
 11. The methodfor fire polishing glass containers as claimed in claim 7, including thestep of: moving the burners forward to a first distance (d1) byprojecting the heat flow into a first predefined area of the containersthat are continuously moving on the conveyor belt; moving the burnersback at a distance (d2) to be placed in a second predefined area of thecontainers and advancing the burners at the same speed of conveyor beltuntil a distance (d2 n); moving the burners back at a distance (d3) toplace said burners in a third pre-defined area for each container andmoving the burners forward at the same speed as the conveyor belt (A)projecting the heat flow to the third pre-defined area of each containeruntil a distance (d3 n) is reached; and, moving the burners back to astarting distance DI once the fire polishing step of the containers hasfinished.
 12. The method for fire polishing glass containers inaccordance with claim 7, comprising the steps of: adjusting the burnersto direct a heat flow to all containers in a first container area in afirst time period t1 and distance d1; adjusting the burners to a secondarea of containers to direct heat flow to the selected area in a secondtime period t2 and distance d2; adjusting the burners towards a thirdarea of containers for directing a heat flow to a third selected area ina third time period t3 and distance d3, until to reach the predeterminedadvancing distance DA; and moving the burners back to a startingdistance DI, once the polishing step of the containers has been carriedout.